Fully bio-based thermosetting polyimine vitrimers with excellent adhesion, rapid self-healing, multi-recyclability and antibacterial ability

Traditional thermosetting materials cannot be degraded, recycled, or reprocessed once they attain their end-of-life causing environmental pollution. Using renewable feedstocks to develop covalent adaptive networks (CANs) based on dynamic covalent bonds can make up for the above shortcomings. The design of new polymeric materials using renewable feedstocks is consistent with the concept of sustainability practices. Herein, castor oil, cysteamine and vanillin are used as building blocks to construct fully bio-based thermosetting polyimine vitrimers through imination between cysteamine functionalized castor oil and divanillin. Owing to its unique structure containing flexible chains, aromatic hydrocarbon and imine bonds, polyimine vitrimers integrate fine mechanical properties, good thermal stability, excellent adhesion, rapid self-healing performance, degradability, recyclability and antibacterial ability. Specifically, the tensile strength of 5.21 MPa, lap-shear strength of 6.07 MPa on 304 stainless steels, self-healing within 30 min at 80 °C, and antibacterial rate against Staphylococcus aureus and Escherichia coli > 90% are observed for this fully bio-based polyimine vitrimers. Additionally, discarded materials can be recovered multiple times for repeated usage by thermo-compression reprocessing and solvent treatment. The original monomer DV is obtained by degradation under 1 M aqueous acetic acid solution with a recovery rate of 92.7%. Therefore, this work will provide a new research strategy for the application of multifunctional bio-based polymer materials, especially in adhesives.